Magnetic tape is frequently used to store digital data thereon. Such tape may be housed in a tape cartridge that protects the tape from damage. A leader block attached to a free end of the tape is used to withdraw the tape from the cartridge for read/write operations.
Read/write operations are performed by a tape transport that is configured to receive the cartridge. A threading mechanism, such as a threading or loading post, grabs the leader block and pulls it free from the cartridge. The threading mechanism then pulls the leader block through a series of guide posts or bearings, across a longitudinal read/write head, and into a slot in a take-up reel to thereby thread the tape through the tape transport. Once threaded, the tape from the cartridge can be driven across the read/write head for data transfer operations, and wound on a hub of the take-up reel.
The leader block and the take-up reel are precisely manufactured so that when the leader block is inserted into the slot in the take-up reel, the slot is sufficiently closed by an end of the leader block to create a relatively smooth surface on the hub of the take-up reel. Ideally, the leader block should cover the slot such that the interface between the end of the leader block and the hub is perfectly smooth. Such a perfectly smooth interface, however, is not practical to manufacture. Therefore, small discontinuities between the leader block and the hub are always present. Such discontinuities can cause impressions in the first wraps of the tape around the hub. These impressions may affect the retrievability of data stored on the tape, which results in data errors.
To ensure data integrity, a known practice involves not writing data to the portions of the tape having impressions. For example, if the first 100 wraps of the tape are effected by tape impressions, then no data is stored on the first 100 wraps of the tape. Such a practice, however, results in wasted data storage capability and wasted time.
U.S. Pat. No. 5,431,356 discloses a take-up reel assembly that is configured to reduce tape impressions. The take-up reel assembly includes a take-up reel having radiused hub edges, and a leader block that also has radiused edges. The edges of the leader block mate with the hub edges to form a continuous, relatively smooth surface on which tape may be wound.